WASHINGTON — The nation’s lifelines — its roads, airports, railways, and transit systems — are getting hammered by extreme weather beyond what their builders imagined, leaving states and cities searching for ways to brace for more catastrophes like Hurricane Sandy.

Even as they prepare for a new normal of intense rain, historic floods, and record heat waves, some transportation planners find it too politically sensitive to say aloud the source of their weather worries: climate change.

Political differences are on the minds of the American Association of State Highway and Transportation Officials, whose advice on the design and maintenance of roads and bridges is closely followed by states.

The association recently changed the name of its Climate Change Steering Committee to the less controversial Sustainable Trans­portation, Energy Infrastructure and Climate Solutions Steering Committee.

Still, there is a recognition that the association’s guidance will have to be updated to reflect the new realities.

‘‘There is a whole series of standards that are going to have to be revisited in light of the change in climate that is coming at us,’’ said John Horsley, the association’s executive director.

In the latest and most severe example, Sandy inflicted the worst damage to the New York subway system in its 108-year history, halted Amtrak and commuter train service to the city for days, and forced cancellation of thousands of airline flights at three airports in New York and New Jersey.

Wild weather is taking a toll on transportation across the country. Last year flooding threatened to swallow up the Omaha airport, which sits on a bend in the Missouri River. The ground beneath the airfield became saturated, causing about 100 sinkholes and ‘‘soil boils’’ — uplifted areas of earth where water bubbles to the surface.

Record-smashing heat from Colorado to Virginia last summer caused train tracks to bend and highway pavement to buckle. A US Airways jet was delayed at Washington’s Reagan National Airport after its wheels got stuck in a soft spot in the tarmac.

States and cities are trying to come to terms with what the change means and how to prepare for it. Transportation engineers build highways and bridges to last 50 or even 100 years. Now they are reconsidering how to do that, or even whether they can, with so much scientific uncertainty.

Making transportation infrastructure more resilient will be expensive, and much of it is already overdue for repair or replacement.